Insulation means for electrical apparatus



June 14, 1949.

J. 'M. ENGLAND 2,473,332

INSULATION MEANS FOR ELECTRICAL APPARATUS Filed May 26, 1944 LJ'HHHHIHIIIHIIIIHHHIIIIIIIHHIII no.5. 3 f

H INVENTOR J, M.ENGLAND ATTORNEY Patented June 14, 1949 l 1-; INSULATIO "MEANs Foa ELECTRICAL IVAPPARATUS fiilppl'ication Ma'y 26, 1944,'Se!ia1-No. 537,511

2""- Claims. 1

My invention relates-toelectricalapparatusand more particularly to improvedinsulation means for the conductorslo'ts of'an'electricalapparatus such as a motor orgenerator.

One of the 'objects'of my inventionisto pfovide specially constructed insulationstrips ior "mounting in conductor slots prior'totheplacing of the conductors therein.

Another object of my'in'tenti'on' is to provide slot insulation means which can "be readily installed in the slots and automatically held-therein without the necessity of special holding'- means.

Yet another object of my invention isto-provide individual sheets "otinsulation material for mounting in conductor 'slots andthiis- 'eli minate the wastage of insulation matrial present 'in the use of a continuousstrip passing intoan'd'out of successive slots.

Still another object of myinve'ntion -is'taprovide improved insulation means' for the conductor slots of an electrical:-'appa'ratus wvhicm when installed, will not decrease:the' width 'of the slot opening through which the-conductors must be passed duringwinding.

Other objects of my: invention Will -become ap parent from the following description tak'en in connection with'the accompanying'cdrawings in which Figure 1 is an endlviewl oii a rotorishowing my improved pape'rrinsulatiomsheet positioned in one of the conductor slots ;Figure -2'is a top' view of the rotor, showing it as' prepare'd foi iwinding; Figure 3 is a sectionalview 'tak'en onthe line 3--3 of Figure 1, said-view radditionally showing-the end insulation plate irr position Figure .4- isza'perspective View of the-insulation -sheet formed for assembly in a slot Figure 5 is a' plan viewof the sheet as cut from a strip of -paper; Flgure 6 'is a View showing the' manner in which thel insulation sheet can beshortened for use:- n' 'slots of lesser length; andFigures-q and18arc: views showing a modified construction.

Referring-to the drawings in detait and 'first to Figures 1 to 5, my: inventionis shown asembodied instead of being notched,theends may be merely slit longitudinally? The-notches "are arranged so that tabs 4 "are' formed in each end of -the"main body 3'of'the sheet, said tabs lying on*-'opposite sides of the longitudinal axis-ofsaid'sheetz Cross scores 5 are prov'idedbetween the tabs andinthe main body of the sheet, said scdresbeing slightly spaced inwardly-of theinner' ends of the notches. This insulation sheet'is adapted to-be placed in each conductor receiving 'sI-ot '6 of the rotor I shown'in Figures 1, 2, and3; said-rotor being of well-known construction and-carried 'on the rotor shaft 8. -The slots -6 havereduced openings l at the surface of- -the=rotor and resulting from-the under-cutting 'of the "portions I 0 of the rotor-reinclining-between the-slots.

I To 'rriount'the'insulati'on sheet 'in therot'orsmt 1 and thereby provide insulation' between"theeconshown in Figure 4.- The sheet i-is -nowfready for insertion in-the slot and is positioned therein by pushing it through therreduced-opening' 9 in-the rotor'surface with the 1 curved -:portion einaering the slot first. As'soon as it' is completely'received in the slot; the side's :wil l"springcoutwardly and the sheet will beheld in-' positionby -the edgesengaging the under-cutsurfaces of-the rotor portioris I 0." In this position the s'heet cov'ersib'oth l the side walls and bottom walls of theslots.

The length: of the bodyofthei-s'he'et between" the scores correspondsito ithe=length oicthe 'sloth's Thus tabs 4 on the sheet, which extendcaway "from-the bodyvof the "sheet due toltheifolding at the scores,

arenow in'a position where1they:overlie the-xend in insulation means for the conductors-receiving slots of a rotor, but it' is to' beg'understobd that it can be employed in -anyliconducton receiving slot whether in a rotor ow -statoror 'othervmember.

made for assembly In this 'form it comprises a single sheet I of-insulation material such a's special paper of fairly heav-ybody 'similar to light cardboard-(shown exaggerated in thicknessfin the i provided at its end with notches 2 which may be surfaces of the rotor iadjacent'thezopen -ends of the'slot. By having .the scores at theplacesindi- -cated, that is slightly ispaced linwardly fromuthe inner end of thenotchaa; small turnedzoyervportion indicated at willresulttwhich willloverlie z the corner orwedge atthezendsiioftthevbottom of Figure 5 shows the insulationi meansras it c'an be the slot, thereby-insulating this corner.

: 'Priorrt'o being wound rotors are provideclitwith insulation end plates or 1 members; :1. Theses-members are of 'fairlyiheavywfiber.boardiandiconform rliin shape to the rcross secti'onlof the: rotomthat is, drawing) This sheet is of rectangulan shape and theyi havelslots the-same size and'ishapeiasmthe rotorrslots. and rteethvzofv the :same isizeliand-vtzshape of U -shap'egasshowmfoi orilsonie otherashape', or 5 tiieirotorrportiohs:l.0iz-isuchifendiplatestfliare shown in Figures 2 and 3. They are held against the end surfaces of the rotors by temporary collars l3 and I4 (Figure 2) which may also be made of fairly heavy fiber paper and secured to the rotor shaft by any suitable means. When my improved insulation sheet is used for the rotor slots, these end plates I2 are employed to clamp tabs 4 and the slightly turned over portions ll against the end surface of the rotor and thereby firmly hold the sheet in the slot and positively prevent shifting either longitudinally, laterally, or radially. Thus it is seen that no gluing or other special means is necessary to hold the sheet in the slot. Also, the entire slot is properly insulated including the corners at the juncture of the walls of the slot and the end surfaces of the rotor.

From the foregoing it is seen that my improved insulation sheet is very simple in construction and easily assembled. When assembled it is firmly held in position by the usual end insulation plates. The sheet provides full insulation for the slot. Also, the openings of the slot at the rotor surface are not decreased in width by the insulation sheet as is the case when a sheet of paper from a roll is passed in and out of successive slots. My sheets also do not result in any waste of insulation material as is the case when a strip of insulation paper goes from one slot to another.

How the insulation sheet can be used for slots having a shorter length than that for which the sheet was cut is shown in Figure 6. The body 3 of the sheet is out in two to form two sheets [5 and I6 and the out ends are overlapped. By means of this cutting and overlapping, a rewinding shop need only buy one length of insulation sheet for several lengths of rotor slots, this length being the one for the slots of the longest rotor of the several rotors. Fewer different sheet lengths will be required to be made or kept in stock.

The modified insulation means shown in Figures 7 and 8 also comprise a sheet I with the cross score 5 adjacent the end shown. The end of the sheet has a curved cut ll the ends of which are spaced slightly from the cross score as shown. There is also provided an axial cut 53 extending from the end edge to the curved out. These cuts form the tabs 4 and a small central tab l9. When the sheet is bent and placed in the rotor slot, as shown in Figure 8, the tabs 4' will overlie the end surface of the rotor laterally of the slot and the tab l9 will cover the corner or edge at the end of the bottom of the slot. The arrangement insures that the entire end corner or edge of the slot will be insulated. The end plates when positioned on the rotor will cover all the tabs and hold the insulation sheet from shifting.

Being aware of the possibility of modifications in the particular structure herein described without departin from the fundamental principles of my invention, I do not intend that its scope be limited except as set forth by the appended claims.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. An insulation means for placing in electrical conductor receiving slots comprising a sheet of insulation material rectangular in shape, notched at one end to provide holding tabs on opposite sides of its longitudinal axis, and cross scored slightly inwardly from the inner end of the notch so that when the sheet is turned upon itself about its longitudinal axis for reception in the slot the sheet can also be bent at the cross score to thus position the holding tabs in later- I will cover the bottom and side walls of the slot and have its side edges positioned inwardly of the slot opening, said sheet being provided with tab means at one end arranged to be positioned to extend laterally outwardly, and means for holding said tab means against the end surface of the member adjacent the slot.

3. In electrical apparatus, the combination with a member having conductor receiving slots, of insulation means for a slot comprising a sheet of insulating material of such width that when turned upon itself about its longitudinal axis it will cover the bottom and side walls of the slot and have its side edges positioned inwardly of the slot opening, said sheet being of greater length than the slot in order to provide end portions which can be positioned to extend laterally outwardly for cooperation with the end surfaces of the member adjacent the slot, and end members for clamping the end portions of the sheet against the end surfaces of the member.

4. An insulation means for conductor receiv ing slots of an electrical apparatus, said means comprising two sheets of insulation material each adapted to be turned upon itself to provide a member of U-shaped cross section and of such length that when placed in the slot there will be overlapping relation of the inner ends, each of said sheets being provided at its unlapped end with holding tab means extending laterally outwardly with respect to the sheet when received in the slot.

5. In electrical apparatus, the combination with a member having conductor receiving slots, of insulation means for a slot comprising two sheets of insulating material positioned in the slots so that one end of one sheet is in overlapping relation to one of the other sheets, each of said sheets being of such width that when turned upon itself about its longitudinal axis it will cover part of the bottom and side walls of the slot and have its side edges positioned inwardly of the slot surface opening, each of said sheets being provided at its unlapped end with tab means positioned outside the slot, and end members associated with the slotted member for clamping the tab means against the end surfaces of the slotted member.

6. An insulation sheet for conductor receiving slots comprising a body portion of rectangular shape having a cross score spaced from one end and provided with cuts extending inwardly from the end edge but short of the score to thereby provide portions outwardly of the score for Covering the end edges of the slot when the sheet is turned upon itself about a longitudinal axis for reception in the slot and bent at the score so that the portion between the end edge and the score extends laterally outwardly.

7. An insulation sheet for conductor receiving slots comprising a body portion of rectangular shape having a cross score spaced from one end edge and provided with cuts extending inwardly from the end edge toward the cross score for forming a central narrow tab and tabs on each side thereof, said cuts being of such length that no part of the sheet closely adjacent the score will be cut to thereby provide a covering for the end edge of the slot when the sheet is placed in 5 the slot after turning the sheet on itself about a longitudinal axis and folding it at the cross score so that all the portions between the score and the end edge extend laterally outwardly, said sheet being of such Width that when turned a U-shaped channel will result which is of less height than the depth of the slot.

JAMES M. ENGLAND.

REFERENCES CITED Number UNITED STATES PATENTS Name Date Kolben Aug. 16, 1892 Sandfield Dec. 18, 1928 Thomas Jan. 19, 1932 Money Jan. 28, 1936 Prindle Sept. 19, 1939 Reaume Mar. 5, 1940 Badeau July 15, 1941 Ferguson May 25, 1943 

